Organisms classified as gram positive bacteria, for example, Streptococcus pyogenes, are known to be pathogenic in humans. Such organisms are the causative agents in Strep throat and have been implicated in complications such as post-streptococcal glomerulonephritis and rheumatic fever. Accordingly, prompt diagnosis and treatment of infections caused by these organisms is imperative in medical practice.
Streptococcus pyogenes, in particular, possesses a group of antigens consisting of a carbohydrate (rhamnose and N-acetyl-glucosamine) bound to the peptidoglycan of the cell wall, and are classified on this basis as Group A Strep. Diagnostic assays for detecting Group A strep can therefore be designed to rely upon the ability of antibody generated in animals to detect the Group A carbohydrate antigen. Since much of this antigen is internal to the organism, exposure of the antigen by mechanical, chemical or enzymatic means aids in increasing the sensitivity of the assays. Conventionally, the carbohydrate antigen has been extracted chemically from whole cells or cell walls by hot formamide, autoclaving in the presence pf HCl (Rantz-Randall method) or through the generation of nitrous acid. Enzymatic release of the antigen has been effected through the use of enzymes from the soil microorganisms of species Streptomyces, e.g., Streptomyces albus, Streptomyces globesporus, and Streptomyces griseus, as well as through the use of proteolytic enzymes like trypsin.